dropdownlis控制gridview的联动

我是初学者，我希望可以改变下拉列表中的选项后，gridview显示不同表中的内容，如何实现？不同的表字段不同，BoundField写死的话肯定不行，不知道gridview中能否在后台里操作BoundField？
我现在希望可以像操作datatable那样给gridview添加行，可行吗？或者我的要求怎么才能实现呢？

解决方案 »

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<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="student_Default" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:GDMSConnectionString %>"
            SelectCommand="SELECT * FROM [class]"></asp:SqlDataSource>

    </div>
        <asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:GDMSConnectionString %>"
            SelectCommand="SELECT * FROM [student] WHERE ([stu_class] = @stu_class)">
            <SelectParameters>
                <asp:ControlParameter ControlID="DropDownList1" Name="stu_class" PropertyName="SelectedValue"
                    Type="String" />
            </SelectParameters>
        </asp:SqlDataSource>
        <asp:DropDownList ID="DropDownList1" runat="server" AppendDataBoundItems="True" AutoPostBack="True"
            DataSourceID="SqlDataSource1" DataTextField="class" DataValueField="class">
        </asp:DropDownList>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="stu_id"
            DataSourceID="SqlDataSource2">
            <Columns>
                <asp:BoundField DataField="stu_id" HeaderText="stu_id" ReadOnly="True" SortExpression="stu_id" />
                <asp:BoundField DataField="stu_name" HeaderText="stu_name" SortExpression="stu_name" />
                <asp:BoundField DataField="stu_class" HeaderText="stu_class" SortExpression="stu_class" />
                <asp:BoundField DataField="sex" HeaderText="sex" SortExpression="sex" />
                <asp:BoundField DataField="imgurl" HeaderText="imgurl" SortExpression="imgurl" />
            </Columns>
        </asp:GridView>
    </form>
</body>
</html>
以Northwind数据库为例：假设在web.config里已经有了连接字符串配置，如：
<connectionStrings>
<add name="NorthwindConnectionString" connectionString="Data Source=.\sqlexpress;Initial Catalog=Northwind;Integrated Security=True" providerName="System.Data.SqlClient"/>
</connectionStrings>前台（注意，这里的GridView必须是EnableViewState="false"):<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
            <asp:ListItem Value="Product表">Product表</asp:ListItem>
            <asp:ListItem Value="Suppliers表")>Suppliers表</asp:ListItem>
        </asp:DropDownList>
        <asp:GridView ID="GridView1" runat="server" EnableViewState="false">
        </asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"></asp:SqlDataSource>
后台：protected void Page_Load(object sender, EventArgs e)
{
        for (int i = 0; i < GridView1.Columns.Count; i++)
            GridView1.Columns.RemoveAt(i);                if (DropDownList1.SelectedValue == "Product表")
        {

            BoundField productID = new BoundField();
            productID.DataField = "ProductID";
            productID.HeaderText = "Product ID";
            GridView1.Columns.Add(productID);            BoundField productName = new BoundField();
            productName.DataField = "ProductName";
            productName.HeaderText = "产品名称";
            GridView1.Columns.Add(productName);            SqlDataSource1.ConnectionString = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
            SqlDataSource1.SelectCommand = "select ProductID, ProductName from Products";
            GridView1.DataSourceID = SqlDataSource1.ID;
            GridView1.AutoGenerateColumns = false;
        }
        else
        {
            BoundField supplierID = new BoundField();
            supplierID.DataField = "SupplierID";
            supplierID.HeaderText = "Supplier ID";
            GridView1.Columns.Add(supplierID);            BoundField companyName = new BoundField();
            companyName.DataField = "CompanyName";
            companyName.HeaderText = "公司名";
            GridView1.Columns.Add(companyName);
            SqlDataSource1.ConnectionString = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
            SqlDataSource1.SelectCommand = "select SupplierID, CompanyName from Suppliers";
            GridView1.DataSourceID = SqlDataSource1.ID;
            GridView1.AutoGenerateColumns = false;        }
}
通过GridView添加新行可以参考这里：Inserting a New Record from the GridView’s Footer
前台应该是这样。<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True">
            <asp:ListItem Value="Product表">Product表</asp:ListItem>
            <asp:ListItem Value="Suppliers表">Suppliers表</asp:ListItem>
        </asp:DropDownList>
        <asp:GridView ID="GridView1" runat="server" EnableViewState="false">
        </asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"></asp:SqlDataSource>
非常感谢namhyuk ，我习惯用手写的数据源，下面是我实现的一个例子，把GridView1.AutoGenerateColumns = False加到Me.GridView1.DataBind()之前就可以控制只显示显示2个字段了。 If DropDownList1.Text = "05" Then            Dim apply_id As New BoundField()
            apply_id.DataField = "apply_id"
            apply_id.HeaderText = "身份证号码"
            GridView1.Columns.Add(apply_id)            Dim job As New BoundField()
            job.DataField = "scholor_name"
            job.HeaderText = "申请工作"
            GridView1.Columns.Add(job)
            Dim objDataSet As New DataSet
            Dim objCon As OleDbConnection
            Dim objDataAdapter As OleDbDataAdapter
            Dim strDbCon, strSQL As String            ' OLEDB提供者字串
            strDbCon = conStr
            ' 建立Connection对象
            objCon = New OleDbConnection(strDbCon)
            strSQL = "SELECT * FROM [financing].[dbo].[scholar_social] "
            ' 建立DataAdapter对象
            objDataAdapter = New OleDbDataAdapter(strSQL, objCon)
            ' 建立CommandBuilder对象产生DataAdapter的SQL命令
            Dim objCmdBuilder As OleDbCommandBuilder = _
                      New OleDbCommandBuilder(objDataAdapter)            ' 将取得的记录数据填入DataSet对象
            objDataAdapter.Fill(objDataSet, "S")            Me.GridView1.DataSource = objDataSet.Tables("S").DefaultView
            GridView1.AutoGenerateColumns = False
            Me.GridView1.DataBind()
        End If